Infectious diseases continue to represent the most important global health threat to mankind; yet inadequate numbers of physician-scientists are being trained who are prepared for academic research careers that can impact our understanding of the pathogenesis and treatment of infectious diseases. We propose the continuation of the UT Southwestern (UTSW) Infectious Diseases postdoctoral training program to train physician-scientists to perform cutting edge basic science research related to host-pathogen interactions. This program provides training for Adult and Pediatric Infectious Diseases Fellows (as well as Pulmonary and Digestive and Liver Fellows who are interested in host-pathogen interactions). The overall goal of this program is to train physician-scientists for successful careers in academic infectious diseases-related research. Specific goals of the research training are for trainees to: (1) develop proficiency in state-of-the art- techniques relevant to infectious diseases research in the area of host-pathogen interactions; (2) gain expertise in a relevant area of biomedical science, such a microbial genetics, immunology, cell biology, biochemistry, or pharmacology; (3) gain expertise and independence in generating strong research hypotheses and in rigorous experimental design and data interpretation; and (4) complete a mentored research project that leads to one or more first-authored peer reviewed publications and NIH career development award applications. These goals will be accomplished by a combination of (1) intensive supervised basic science research experience in the laboratories of our 22 program training faculty (all of whom are outstanding NIH-funded scientists performing exciting work in the field of host-pathogen interactions); (2) a comprehensive didactic curriculum that includes required courses and electives in biomedical sciences, ethics, statistics, and career development; (3) active mentoring and career development by the primary mentor and thesis committee members; and (4) the opportunity to train in a highly interactive and stimulating interdisciplinary scientific environment. This comprehensive and multi-faceted approach will result in the training of post-doctoral fellows in Infectious Diseases research with strong potential to succeed in academic research careers and strong potential to perform basic science research that will impact the prevention and/or treatment of infectious diseases.